This invention relates to a method and apparatus for changing the surface characteristics of a spun textile yarn. More particularly, this invention relates to a method and apparatus for suppressing the hairiness of such yarn while removing loose fiber and contamination. Still more particularly, this invention relates to a method and apparatus for producing desired surface characteristics using a suitable air jet nozzle. Still more particularly, this invention relates to a new use for existing air jet nozzles to alter the physical characteristics of the surface of previously-spun yarn and to control the hairiness of such yarn.
In the textile arts, significant attention has been paid to consideration of the effect of yarn hairiness and its impact on weaving performance. It is a general objective in the art to control the final hairiness of the warp yarn so that yarns in the sheet will separate cleanly and easily. Unfortunately, excessive warp yarn hairiness and clinging affect production yields, quality of final product, and housekeeping efforts. A major difficulty with high yarn hairiness is that clinging hair fibers between warp ends tend to prevent the formation of a clear front shed on the weaving machine.
A low yarn hairiness can be obtained in a spinner-bobbin of yarn by controlling traveler type and weight, condition of rings, and plumbing of spindles. Moreover it is desired to make uniform the degree of hairiness on a spindle-to-spindle basis, and to achieve a good average hairiness wherein the ratio of the high to the low is limited.
However, the development and commercial acceptance of air jet weaving in the late 1970's has increased the concern of weavers about the effect of hair fibers that protrude from the surface of short staple spun yarns. Indeed, air jet weaving generally requires yarns of higher qualities than shuttle weaving to achieve high productivity. An unclear front shed may obstruct the flight of the filling yarn, resulting in a filling stop that was warp induced.
It is also known that winding a ring spun yarn causes significant increases in yarn hairiness, sometimes on the order of 100 to 500 per cent. Thus, at the winding stage for spun yarn, prior efforts to suppress or control hairiness in spinning are unfortunately largely negated. Heretofore, no practical method or apparatus was available to wind a ring spun yarn without causing a significant increase in measurable hairiness.
A number of prior efforts to lower ultimate sized yarn hairiness have been proposed, but without significant success. For example, efforts to modify the ring spinning machines were not successful in producing a yarn with better locking of the outermost fibers. In the past, however, it had been established that yarn spun from spaced double-creeled roving approached the desired surface properties, but such spinning is no longer widely practiced because of economic reasons. Experimental efforts focused on winding including gas singeing, mechanical cutting, and scraping but no such efforts provided the desired dramatic results.
It was also known that tension had a bearing on wound yarn hairiness in that higher winding tension generally resulted in lower wound yarn hairiness. It is believed that this phenomenon occurs because long hair fibers are stripped from the yarn surface when passing through highly-loaded tension discs, thus improving the overall surface characteristics.
Nevertheless, despite such efforts to improve the surface characteristics of spun yarn and in particular its hairiness at various stages of the yarn handling processes, only a limited success has been achieved. Thus, it is an overall objective of this invention to control the physical characteristics of spun yarn, and especially the hairiness of spun yarn especially after spinning and winding.
By way of further background, yarn hairiness is usually defined as fiber ends and fiber loops protruding above the yarn 10 surface, where fiber loops account for about two-thirds of the yarn hairiness and fiber ends account for the other third. A number of techniques are available for measuring yarn hairiness, although currently measurement by optical and photographic means are generally preferred. In a typical, well-accepted measuring system, the hairiness of the yarn is determined by counting the number of fibers extending beyond the apparent surface of the yarn, and displaying the count for a predetermined period of time to obtain an objective count of the hairiness of the yarn for a unit length of yarn.
It is thus an overall objective of this invention to improve the surface characteristics of spun yarn.
It is an additional objective of this invention to improve the surface characteristics of spun yarn by controlling yarn hairiness.
It is still another objective of this invention to improve yarn hairiness in spun yarn by using an air jet nozzle or air vortex produced by a nozzle.
It is another overall objective of this invention to improve the physical characteristics of the surface of spun yarn by passing the spun yarn through an air jet nozzle.
It is still another specific objective of this invention to improve the physical characteristics of the surface of spun yarn by passing the spun yarn through an air jet nozzle in a direction opposite to the yarn direction during spinning.
It is yet another objective of this invention to improve the physical characteristics of the surface of spun yarn by passing the spun yarn through an air jet nozzle and controlling the angle of exit from the nozzle.
It is yet another objective of this invention to remove dust, loose fiber, seed coat contamination, and other impurities in spun yarns by passing the spun yarn through an air jet nozzle or air vortex produced in a nozzle.
It is still another general objective of the invention to remove contamination from yarn during a winding process.
It is another objective of the invention to modify a yarn with a jet nozzle to improve contamination removal during winding.
These and other objectives and aims of the invention will become apparent from a written description of the invention which follows when taken in conjunction with the accompanying drawings.